Question

General combining ability and Specific combining
ability​

Answer 1

Answer:

Explanation:

Evaluation of Inbreds for General Combining Ability

Inbred lines are evaluated for their general combining ability (GCA). There are three methods used: top cross, poly cross, and single cross. In top cross, crosses are made between inbreds and either a tester or an open-pollinated variety. This is also known as an inbred–variety cross. In poly cross, selected inbreds are allowed to intermate by open pollination with a random sample of pollen from a number of selected lines. These lines are grown in the same nursery. The lines are grown at random in a poly cross-nursery with a minimum of 10 replications. Free outcrossing takes place and seed set on a line in replicates is pooled and the performance tested. In the third method, all possible crosses are made among selected inbreds, each in isolation. The crosses are evaluated for their GCA, yield, or other desirable traits in replicated trials compared with checks. The lines performing better on the basis of GCA are selected as constituents of the synthetic variety.

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